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Date: Thu, 01 Nov 2012 15:35:40 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Yinghai Lu <yinghai@...nel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Linux PM list <linux-pm@...r.kernel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Len Brown <lenb@...nel.org>,
Mathias Nyman <mathias.nyman@...ux.intel.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Lv Zheng <lv.zheng@...el.com>,
Huang Ying <ying.huang@...el.com>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>, x86 list <x86@...nel.org>,
Tony Luck <tony.luck@...el.com>
Subject: Re: [PATCH 5/5] ACPI: Add support for platform bus type
On Wednesday, October 31, 2012 11:34:24 PM Yinghai Lu wrote:
> On Wed, Oct 31, 2012 at 2:36 AM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> > From: Mika Westerberg <mika.westerberg@...ux.intel.com>
> >
> > With ACPI 5 it is now possible to enumerate traditional SoC
> > peripherals, like serial bus controllers and slave devices behind
> > them. These devices are typically based on IP-blocks used in many
> > existing SoC platforms and platform drivers for them may already
> > be present in the kernel tree.
> >
> > To make driver "porting" more straightforward, add ACPI support to
> > the platform bus type. Instead of writing ACPI "glue" drivers for
> > the existing platform drivers, register the platform bus type with
> > ACPI to create platform device objects for the drivers and bind the
> > corresponding ACPI handles to those platform devices.
> >
> > This should allow us to reuse the existing platform drivers for the
> > devices in question with the minimum amount of modifications.
> >
> > This changeset is based on Mika Westerberg's and Mathias Nyman's
> > work.
> >
> > Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
> > Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> > drivers/acpi/Makefile | 1
> > drivers/acpi/acpi_platform.c | 285 +++++++++++++++++++++++++++++++++++++++++++
> > drivers/acpi/internal.h | 7 +
> > drivers/acpi/scan.c | 16 ++
> > drivers/base/platform.c | 5
> > 5 files changed, 313 insertions(+), 1 deletion(-)
>
> this patch is too big, and should be split to at least two or more.
>
> > create mode 100644 drivers/acpi/acpi_platform.c
> >
> > Index: linux/drivers/acpi/Makefile
> > ===================================================================
> > --- linux.orig/drivers/acpi/Makefile
> > +++ linux/drivers/acpi/Makefile
> > @@ -37,6 +37,7 @@ acpi-y += processor_core.o
> > acpi-y += ec.o
> > acpi-$(CONFIG_ACPI_DOCK) += dock.o
> > acpi-y += pci_root.o pci_link.o pci_irq.o pci_bind.o
> > +acpi-y += acpi_platform.o
> > acpi-y += power.o
> > acpi-y += event.o
> > acpi-y += sysfs.o
> > Index: linux/drivers/acpi/acpi_platform.c
> > ===================================================================
> > --- /dev/null
> > +++ linux/drivers/acpi/acpi_platform.c
> > @@ -0,0 +1,285 @@
> > +/*
> > + * ACPI support for platform bus type.
> > + *
> > + * Copyright (C) 2012, Intel Corporation
> > + * Authors: Mika Westerberg <mika.westerberg@...ux.intel.com>
> > + * Mathias Nyman <mathias.nyman@...ux.intel.com>
> > + * Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/device.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +
> > +ACPI_MODULE_NAME("platform");
> > +
> > +struct resource_info {
> > + struct device *dev;
> > + struct resource *res;
> > + size_t n, cur;
> > +};
> > +
> > +static acpi_status acpi_platform_count_resources(struct acpi_resource *res,
> > + void *data)
> > +{
> > + struct acpi_resource_extended_irq *acpi_xirq;
> > + struct resource_info *ri = data;
> > +
> > + switch (res->type) {
> > + case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
> > + case ACPI_RESOURCE_TYPE_IRQ:
> > + ri->n++;
> > + break;
> > + case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
> > + acpi_xirq = &res->data.extended_irq;
> > + ri->n += acpi_xirq->interrupt_count;
> > + break;
> > + case ACPI_RESOURCE_TYPE_ADDRESS32:
> > + if (res->data.address32.resource_type == ACPI_IO_RANGE)
> > + ri->n++;
> > + break;
> > + }
> > +
> > + return AE_OK;
> > +}
> > +
> > +static acpi_status acpi_platform_add_resources(struct acpi_resource *res,
> > + void *data)
> > +{
> > + struct acpi_resource_fixed_memory32 *acpi_mem;
> > + struct acpi_resource_address32 *acpi_add32;
> > + struct acpi_resource_extended_irq *acpi_xirq;
> > + struct acpi_resource_irq *acpi_irq;
> > + struct resource_info *ri = data;
> > + struct resource *r;
> > + int irq, i;
> > +
> > + switch (res->type) {
> > + case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
> > + acpi_mem = &res->data.fixed_memory32;
> > + r = &ri->res[ri->cur++];
> > +
> > + r->start = acpi_mem->address;
> > + r->end = r->start + acpi_mem->address_length - 1;
> > + r->flags = IORESOURCE_MEM;
> > +
> > + dev_dbg(ri->dev, "Memory32Fixed %pR\n", r);
> > + break;
> > +
> > + case ACPI_RESOURCE_TYPE_ADDRESS32:
> > + acpi_add32 = &res->data.address32;
> > +
> > + if (acpi_add32->resource_type == ACPI_IO_RANGE) {
> > + r = &ri->res[ri->cur++];
> > + r->start = acpi_add32->minimum;
> > + r->end = r->start + acpi_add32->address_length - 1;
> > + r->flags = IORESOURCE_IO;
> > + dev_dbg(ri->dev, "Address32 %pR\n", r);
> > + }
> > + break;
> > +
> > + case ACPI_RESOURCE_TYPE_IRQ:
> > + acpi_irq = &res->data.irq;
> > + r = &ri->res[ri->cur++];
> > +
> > + irq = acpi_register_gsi(ri->dev,
> > + acpi_irq->interrupts[0],
> > + acpi_irq->triggering,
> > + acpi_irq->polarity);
> > +
> > + r->start = r->end = irq;
> > + r->flags = IORESOURCE_IRQ;
> > +
> > + dev_dbg(ri->dev, "IRQ %pR\n", r);
> > + break;
> > +
> > + case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
> > + acpi_xirq = &res->data.extended_irq;
> > +
> > + for (i = 0; i < acpi_xirq->interrupt_count; i++, ri->cur++) {
> > + r = &ri->res[ri->cur];
> > + irq = acpi_register_gsi(ri->dev,
> > + acpi_xirq->interrupts[i],
> > + acpi_xirq->triggering,
> > + acpi_xirq->polarity);
> > +
> > + r->start = r->end = irq;
> > + r->flags = IORESOURCE_IRQ;
> > +
> > + dev_dbg(ri->dev, "Interrupt %pR\n", r);
> > + }
> > + break;
> > + }
> > +
> > + return AE_OK;
> > +}
> > +
>
> could be shared with pci root or pnp devices?
Maybe.
> > +static acpi_status acpi_platform_get_device_uid(struct acpi_device *adev,
> > + int *uid)
> > +{
> > + struct acpi_device_info *info;
> > + acpi_status status;
> > +
> > + status = acpi_get_object_info(adev->handle, &info);
> > + if (ACPI_FAILURE(status))
> > + return status;
> > +
> > + status = AE_NOT_EXIST;
> > + if ((info->valid & ACPI_VALID_UID) &&
> > + !kstrtoint(info->unique_id.string, 0, uid))
> > + status = AE_OK;
> > +
> > + kfree(info);
> > + return status;
> > +}
> > +
> > +/**
> > + * acpi_create_platform_device - Create platform device for ACPI device node
> > + * @adev: ACPI device node to create a platform device for.
> > + *
> > + * Check if the given @adev can be represented as a platform device and, if
> > + * that's the case, create and register a platform device, populate its common
> > + * resources and returns a pointer to it. Otherwise, return %NULL.
> > + *
> > + * The platform device's name will be taken from the @adev's _HID and _UID.
> > + */
> > +struct platform_device *acpi_create_platform_device(struct acpi_device *adev)
> > +{
> > + struct platform_device *pdev = NULL;
> > + struct acpi_device *acpi_parent;
> > + struct device *parent = NULL;
> > + struct resource_info ri;
> > + acpi_status status;
> > + int devid;
> > +
> > + /* If the ACPI node already has a physical device attached, skip it. */
> > + if (adev->physical_node_count)
> > + return NULL;
> > +
> > + /* Use the UID of the device as the new platform device id if found. */
> > + status = acpi_platform_get_device_uid(adev, &devid);
> > + if (ACPI_FAILURE(status))
> > + devid = -1;
> > +
> > + memset(&ri, 0, sizeof(ri));
> > +
> > + /* First, count the resources. */
> > + status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
> > + acpi_platform_count_resources, &ri);
> > + if (ACPI_FAILURE(status) || !ri.n)
> > + return NULL;
> > +
> > + /* Next, allocate memory for all the resources and populate it. */
> > + ri.dev = &adev->dev;
> > + ri.res = kzalloc(ri.n * sizeof(struct resource), GFP_KERNEL);
> > + if (!ri.res) {
> > + dev_err(&adev->dev,
> > + "failed to allocate memory for resources\n");
> > + return NULL;
> > + }
> > +
> > + status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
> > + acpi_platform_add_resources, &ri);
> > + if (ACPI_FAILURE(status)) {
> > + dev_err(&adev->dev, "failed to walk resources\n");
> > + goto out;
> > + }
> > +
> > + if (WARN_ON(ri.n != ri.cur))
> > + goto out;
> > +
> > + /*
> > + * If the ACPI node has a parent and that parent has a physical device
> > + * attached to it, that physical device should be the parent of the
> > + * platform device we are about to create.
> > + */
> > + acpi_parent = adev->parent;
> > + if (acpi_parent) {
> > + struct acpi_device_physical_node *entry;
> > + struct list_head *list;
> > +
> > + mutex_lock(&acpi_parent->physical_node_lock);
> > + list = &acpi_parent->physical_node_list;
> > + if (!list_empty(list)) {
> > + entry = list_first_entry(list,
> > + struct acpi_device_physical_node,
> > + node);
> > + parent = entry->dev;
> > + }
> > + mutex_unlock(&acpi_parent->physical_node_lock);
> > + }
> > + pdev = platform_device_register_resndata(parent, acpi_device_hid(adev),
> > + devid, ri.res, ri.n, NULL, 0);
> > + if (IS_ERR(pdev)) {
> > + dev_err(&adev->dev, "platform device creation failed: %ld\n",
> > + PTR_ERR(pdev));
> > + pdev = NULL;
> > + } else {
> > + dev_dbg(&adev->dev, "created platform device %s\n",
> > + dev_name(&pdev->dev));
> > + }
> > +
> > + out:
> > + kfree(ri.res);
> > + return pdev;
> > +}
> > +
> > +static acpi_status acpi_platform_match(acpi_handle handle, u32 depth,
> > + void *data, void **return_value)
> > +{
> > + struct platform_device *pdev = data;
> > + struct acpi_device *adev;
> > + acpi_status status;
> > +
> > + status = acpi_bus_get_device(handle, &adev);
> > + if (ACPI_FAILURE(status))
> > + return status;
> > +
> > + /* Skip ACPI devices that have physical device attached */
> > + if (adev->physical_node_count)
> > + return AE_OK;
> > +
> > + if (!strcmp(pdev->name, acpi_device_hid(adev))) {
> > + int devid;
> > +
> > + /* Check that both name and UID match if it exists */
> > + status = acpi_platform_get_device_uid(adev, &devid);
> > + if (ACPI_FAILURE(status))
> > + devid = -1;
> > +
> > + if (pdev->id != devid)
> > + return AE_OK;
> > +
> > + *(acpi_handle *)return_value = handle;
> > + return AE_CTRL_TERMINATE;
> > + }
> > +
> > + return AE_OK;
> > +}
> > +
> > +static int acpi_platform_find_device(struct device *dev, acpi_handle *handle)
> > +{
> > + struct platform_device *pdev = to_platform_device(dev);
> > +
> > + *handle = NULL;
> > + acpi_get_devices(pdev->name, acpi_platform_match, pdev, handle);
> > +
> > + return *handle ? 0 : -ENODEV;
> > +}
> > +
> > +static struct acpi_bus_type acpi_platform_bus = {
> > + .bus = &platform_bus_type,
> > + .find_device = acpi_platform_find_device,
> > +};
> > +
> > +static int __init acpi_platform_init(void)
> > +{
> > + return register_acpi_bus_type(&acpi_platform_bus);
> > +}
> > +arch_initcall(acpi_platform_init);
> > Index: linux/drivers/acpi/internal.h
> > ===================================================================
> > --- linux.orig/drivers/acpi/internal.h
> > +++ linux/drivers/acpi/internal.h
> > @@ -93,4 +93,11 @@ static inline int suspend_nvs_save(void)
> > static inline void suspend_nvs_restore(void) {}
> > #endif
> >
> > +/*--------------------------------------------------------------------------
> > + Platform bus support
> > + -------------------------------------------------------------------------- */
> > +struct platform_device;
> > +
> > +struct platform_device *acpi_create_platform_device(struct acpi_device *adev);
> > +
> > #endif /* _ACPI_INTERNAL_H_ */
> > Index: linux/drivers/acpi/scan.c
> > ===================================================================
> > --- linux.orig/drivers/acpi/scan.c
> > +++ linux/drivers/acpi/scan.c
> > @@ -29,6 +29,15 @@ extern struct acpi_device *acpi_root;
> >
> > static const char *dummy_hid = "device";
> >
> > +/*
> > + * The following ACPI IDs are known to be suitable for representing as
> > + * platform devices.
> > + */
> > +static const struct acpi_device_id acpi_platform_device_ids[] = {
> > +
>
> ?
Yes, empty list. We're going to populate it later.
> > + { }
> > +};
> > +
> > static LIST_HEAD(acpi_device_list);
> > static LIST_HEAD(acpi_bus_id_list);
> > DEFINE_MUTEX(acpi_device_lock);
> > @@ -1544,8 +1553,13 @@ static acpi_status acpi_bus_check_add(ac
> > */
> > device = NULL;
> > acpi_bus_get_device(handle, &device);
> > - if (ops->acpi_op_add && !device)
> > + if (ops->acpi_op_add && !device) {
> > acpi_add_single_object(&device, handle, type, sta, ops);
> > + /* Is the device a known good platform device? */
> > + if (device
> > + && !acpi_match_device_ids(device, acpi_platform_device_ids))
> > + acpi_create_platform_device(device);
> > + }
>
> That is ugly! any reason for not using acpi_driver for them.
Yes, a couple of reasons. First off, there are existing platform drivers for
these things already and there's no reason for creating a "glue" layer between
those drivers and struct acpi_device objects. Second, we're going to get rid
of acpi_driver things entirely going forward (the existing ones will be replaced
by platform drivers or included into the ACPI core).
> there is not reason to treat those platform_device different from pci
> root device and other pnp device.
Well, I agree. :-)
So those things you're talking about we'll be platform devices too in the
future.
> something like attached patch. .add of acpi_driver ops could call
> acpi_create_platform_device.
Been there, decided to do it differently this time.
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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